Nuclear medicine is a branch of medicine that uses radioactive materials (e.g., radioisotopes) for various research, diagnostic and therapeutic applications. Radiopharmacies produce various radiopharmaceuticals (i.e., radioactive pharmaceuticals) by combining one or more radioactive materials with other materials to adapt the radioactive materials for use in a particular medical procedure.
For example, radioisotope generators may be used to obtain a solution comprising a daughter radioisotope (e.g., Technetium-99m) from a parent radioisotope (e.g., Molybdenum-99) which produces the daughter radioisotope by radioactive decay. A radioisotope generator may include a column containing the parent radioisotope adsorbed on a carrier medium. The carrier medium (e.g., alumina) has a relatively higher affinity for the parent radioisotope than the daughter radioisotope. As the parent radioisotope decays, a quantity of the desired daughter radioisotope is produced. To obtain the desired daughter radioisotope, a suitable eluant (e.g., a sterile saline solution) can be passed through the column to elute the daughter radioisotope from the carrier. The resulting eluate contains the daughter radioisotope (e.g., in the form of a dissolved salt), which makes the eluate a useful material for preparation of radiopharmaceuticals. For example, the eluate may be used as the source of a radioisotope in a solution adapted for intravenous administration to a patient for any of a variety of diagnostic and/or therapeutic procedures.
In one method of obtaining a quantity of the eluate from the generator, an evacuated container (e.g., an elution vial) may be connected to the generator at a tapping point. For example, a hollow needle on the generator can be used to pierce a septum of an evacuated container to establish fluid communication between the elution vial and the generator column. The partial vacuum of the container can draw eluant from an eluant reservoir through the column and into the vial, thereby eluting the daughter radioisotope from the column. The container may be contained in an elution shield, which is a radiation-shielding device used to shield workers from radiation emitted by the eluate after it is received in the container from the generator.
The same generator may be used to fill a number of containers before the radioisotopes in the column are spent. The volume of eluate needed at any time may vary depending on the number of prescriptions that need to be filled by the radiopharmacy and/or the remaining concentration of radioisotopes in the generator column. One way to vary the amount of eluate drawn from the column is to vary the volume of evacuated containers used to receive the eluate. For example, container volumes ranging from about 5 mL to about 30 mL are common and standard containers having volumes of 5 mL, 10 mL, or 20 mL are currently used in the industry. A container having a desired volume may be selected to facilitate dispensing of a corresponding amount of eluate from the generator column.
Unfortunately, the use of multiple different sizes of containers is associated with significant disadvantages. Hindering substantial movement of the container in the shield is desirable to avoid damage to the container, the shield, and/or the generator. Moreover, some feel it desirable that the position of the container in the shield be consistent from one container to the next so that the container can be accessed in a consistent fashion. One solution would be to have a dedicated shield for each size of container. However, cost and convenience tend to promote the use of a single shield capable of accommodating differently sized containers (one at a time).
A radiopharmacy may attempt to manipulate a conventional shielding device so that it can be used with containers of various sizes. One solution that has been practiced is to keep a variety of different spacers on hand that may be inserted into shielding devices to temporarily occupy extra space in the radiation-shielding devices when smaller containers are being used. This may add complexity and/or increase the risk of confusion because the spacers can get mixed up, lost, broken, and/or used with the wrong container. Some conventional spacers surround the sides of the containers in the shielding-devices, which is where labels may be attached to the containers. Accordingly, the spacers may mar the labels and/or contact adhesives used to attach the labels to the container resultantly causing the spacers to stick to the sides of the container or otherwise gum up the radiation-shielding device. Thus, improved radiation-shielding assemblies and methods of handling differently sized containers for containing one or more radioisotopes would be desirable.